What do you do when your lead actress is expecting a baby, but it wouldn't make sense for her character to also be pregnant?

You have her hold things in front of her growing stomach - laundry baskets, satchels or, in the case of Mariska Hargitay's character, Detective Olivia Benson, big, fat police files.

But what do you do when that actress takes time off to have and enjoy her first child, separating the central partners of NBC's hit, "Law & Order: Special Victims Unit" - one of TV's most popular teams?

Now that's where things get really tricky.

"SVU" executive producer Neal Baer and his writers have concocted a complicated strategy to accommodate the temporary loss of Hargitay, 42, who's taking off for Los Angeles, her hometown, to await the arrival of a son, due June 21.

In addition to logistical challenges - more on that later - Baer's plan necessitated some tinkering with the detective partnership of Hargitay's Benson and Chris Meloni's Elliot Stabler.

That story line went into motion with this week's powerful episode, "Fault." In it, Benson and Stabler are hunting for a recently paroled serial pedophile (Lou Diamond Phillips), who has murdered several members of a family and run off with the two youngest children. The partners eventually track him to a New York bus terminal, and in the violent and emotional showdown, Benson gets slashed. Stabler is torn between coming to her aid and chasing after the pedophile, who has the two kids in tow.

His decision - and Benson's later hesitation at another pivotal moment - lead Stabler and Benson to question if their deep mutual attachment may be hindering their ability to do their jobs.

The episode makes clear that these two love each other, but what kind of love is it? As Meloni told me at the show's start, "We asked Dick Wolf, 'Is there going to be any kind of relationship between us?' And he goes, 'I got one word for you: "Moonlighting.' " And he walked away."

Back then, however, the characters' circumstances were different. Stabler, a father of four, was happily married to his high-school sweetheart. Now, he's single and lonely. And Benson, still ambivalent about having children, is unattached. And she definitely seemed jealous when the newly separated Benson paid too much attention to Dr. Rebecca Hendrix (Mary Stuart Masterson), the police-officer-turned-psychiatrist who sometimes helps them with cases.

Has Wolf's credo changed?

"No," Meloni says firmly. "And I still think Dick is very right about it. Then it becomes a different show and a different way of telling a story. People kind of connect to these characters almost like a mom and dad, I think. Hey, you don't want to picture your mom and dad having sex.

"It's almost on the level of symbolism - (she's) the nurturer, and (he's) the dad, who's going to keep you safe and secure."

Nonetheless, "Fault" leaves viewers wondering about the nature of Benson and Stabler's feelings for each other. And Baer is coy on that matter.

"We'll leave that to the audience. I want to see how the audience interprets it," he says.

The goal of this week's episode, Baer says, "was to stir things up and get them back together, so that they're really doing well together, and then we'll really pull them apart," thus paving the way for temporary replacements.

Next month, Anthony Anderson, who played sound engineer Key in "Hustle & Flow" and bad guy Antwon Mitchell in FX's "The Shield," will briefly come aboard as Stabler's new partner, Manuel Valdez. And as previously announced, Connie Nielsen will do six episodes as a warrant officer who gets paired with Stabler. But she won't arrive until next fall.

"We're going to deal with how Connie and my partnership evolved," Meloni says. "We're all on board that it has to be different. She's different than Mariska, obviously."

Hargitay, who is married to actor Peter Hermann, finished her last pre-baby scenes last week.

"But she's already shot several of next year's shows, and Mariska will still be on for the whole rest of the season," Baer says.

To minimize Hargitay's absence, the cast has been filming two episodes at once, called tandem-shooting (or "tandemonium," as they jokingly dubbed it on the set) - a technique "SVU" generally uses (but more sparingly) each year to get a jump on the following season.

This year, there have been more showcase episodes that spotlight specific cast members and reveal their characters' inner conflicts. In last week's powerful "Venom," for example, Ice-T's Detective "Fin" Tutuola discovered a tragic secret hidden by his ex-wife (Lisa Gay Hamilton). It came to light when Fin's son became a suspect in a murder actually committed by the troubled young man whom Fin had always considered his "nephew" (played by Chris "Ludicris" Bridges).

There was also one in which Hargitay frantically tried to save a little girl who had dialed 911, and another in which Stabler, struggling with a case involving an abusive father, finally showed up on the doorstep of the aforementioned Dr. Hendrix, the comely shrink, and came clean about his own difficult childhood.

"I was very happy about the script, and I was very proud of the work," Meloni says. "For an actor, it really was great, because the thing that you're speaking of, where I have my confessional with Mary Stuart Masterson, that was one whole act, so I got to be onstage basically for 12 minutes as opposed to 2 1/2 minutes. As an actor, I got to have highs and lows, mountains and valleys.

"Neal Baer is always looking for a way to present the material in a different way, whether it's intercutting between two different interrogations, fading from scenes, as opposed to the chunk-chunk ("L&O" trademark sound), using different lighting, different film, writing the script differently. It's keeping it a slightly different product, so viewers can't become complacent."

"SVU," which is based in North Bergen, N.J., will take a break in mid-June, then resume production on Season 8 in late September.

"Everybody's returning. It will be the same 'SVU' that you love," Baer says.

Meanwhile, for the next two months, Meloni will be separated from Hargitay for the first time in the show's history. Will he miss her?

"No, it will be nice," the actor says. "I mean, with complete affection toward Mariska, we deal with each other more than the people we're married to. Even though we have a hiatus, we always come back to the same spot, the same working conditions. This is nice. It's something different."

Hargitay is the "self-appointed" godmother to Meloni's daughter. So, does he expect her to return the favor?

Meloni laughs. "I'm the worst choice you can think of."

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SERIES SUBS

Mother-to-be Mariska Hargitay leaves big shoes to fill on "Law & Order: SVU." In the story line written to accommodate her maternity leave, two actors will temporarily join the unit.

Connie Nielsen: The Danish-born "Gladiator" actress will be "spelling" Hargitay, as Dick Wolf puts it, for six episodes as an NYPD warrants officer on temporary assignment to the special victims unit. Nielsen reported to the set for duty at the end of this week, but she won't be seen on "SVU" until next fall.

Anthony Anderson: The versatile actor, from "Hustle & Flow" and "The Shield," will briefly play Chris Meloni's new partner, Manuel Valdez. He'll show up in "Fat," the first "SVU" episode of the May sweeps.